POWER-OVER-ETHERNET (PoE) POWERED MULTICHANNEL STREAMING AUDIO AMPLIFIER

ABSTRACT

A power-over-Ethernet (PoE) powered multichannel streaming audio amplifier includes a plurality of Ethernet ports each configured to be coupled to an Ethernet cable and capable of receiving power and audio data transmitted over the Ethernet cables. Power supply circuitry connected to the Ethernet ports is configured to combine and manage the power received at the Ethernet ports. A microprocessor subsystem powered by the power supply circuitry is configured to receive and process the audio data to generate output audio signals. A digital audio amplifier powered by the power supply circuitry amplifies the output audio signals received from the microprocessor system. A plurality of audio outputs connected to the digital audio amplifier are each configured to be connected to a different one of a plurality of speaker devices to transmit the audio output signals amplified by the digital audio amplifier to the plurality of speaker devices.

BACKGROUND

The present application relates generally to audio amplifiers and, moreparticularly, to a PoE powered multichannel streaming audio amplifier.

Consumers have had limited accessibility to High Resolution digitalaudio (audio files with greater than 48 kHz sample rate or higher than16-bit audio bit depth). Lenbrook Industries Limited (owner of NADElectronics and Bluesound Music Systems and the applicant of the presentapplication) began development of a new type of High Resolution mediaaudio playback system in 2004 and demonstrated such a system in 2009. By2011, the NAD Masters Digital Suite Home Sound System enabled consumersto experience music via one or more networked playback devices. Thesystem's BluOS™ operating system was expanded to more affordable deviceswith the introduction of the Bluesound brand in 2012. Through a softwarecontrol application installed on a controller (e.g., IR remote, wallmounted controller, smartphone, tablet, computer, voice input device),consumers can play what they desire in any room having a networkedplayback device. They can access High Resolution music files by eachroom with a playback device and group rooms together for synchronousplayback of the same music. The BluOS™ modular software design alsoallows the unification of audio video receiver (AVR) devices, reducingthe cost of software development compared to highly proprietary MCU/DSPsoftware currently used throughout the AVR industry.

Distribution and playback of High Resolution audio throughout largecommercial facilities has typically relied on high-power multichannelaudio amplifiers installed in a dedicated equipment rack. Larger audiosystem installations in commercial settings (e.g., hotels, airports, andrestaurants) typically involve multiple audio equipment racks inequipment rooms distributed throughout the facility. Each audioequipment rack requires the installation of a dedicated mains-voltageelectrical supply circuit, requiring the costly services of a licensedelectrician and safety inspections as required by building codes in mostjurisdictions. The costs become even more apparent in facilitiesundergoing retrofit to upgrade their sound systems, as this requiresadditional effort to modify a facilities structure to place additionalmains-voltage circuits wherever conventional audio amplification isneeded. Alternatives to the costly dedicated electrical circuits havebeen considered for these applications. These typically involvelower-voltage AC and DC electrical sources that reduce the number ofhigh-voltage mains circuits required for each audio amplificationdevice. Cost-reducing solutions include installation of wiring carryinga lower voltage to a compatible audio amplifier device. Generally,installation of wiring carrying less than 48 Volts does not require thecostly services of a licensed electrician. However, these alternativeshave carried two principal drawbacks. The quality of the sound isreduced as there is ultimately less power available from lower voltagepower supply cabling. These lower voltage power supplies and theircabling are usually proprietary and not associated with any standard,leaving commercial system designers with only one option for procuringcable and power conversion equipment manufactured by the audio systemvendor. Some previous solutions were simply low-voltage DC cabling,which did not have the ability to carry digital music services tostreaming audio amplifiers. These long-standing shortcomings highlight aneed for a better technical option for eliminating high licensedelectrician costs and installation challenges for multichannel streamingaudio amplifiers.

BRIEF SUMMARY OF THE DISCLOSURE

A power-over-Ethernet powered multichannel streaming audio amplifier inaccordance with one or more embodiments includes a plurality of Ethernetports each configured to be coupled to an Ethernet cable and capable ofreceiving power and audio data transmitted over the Ethernet cables.Power supply circuitry connected to the Ethernet ports is configured tocombine and manage the power received at the Ethernet ports. Amicroprocessor subsystem powered by the power supply circuitry isconfigured to receive and process the audio data to generate outputaudio signals. A digital audio amplifier powered by the power supplycircuitry amplifies the output audio signals received from themicroprocessor system. A plurality of audio outputs connected to thedigital audio amplifier are each configured to be connected to adifferent one of a plurality of speaker devices to transmit the audiooutput signals amplified by the digital audio amplifier to the pluralityof speaker devices.

A method in accordance with one or more embodiments is disclosed foroperating a multichannel streaming audio amplifier, which is connectedby a plurality of Ethernet cables to power-over-Ethernet enabled powersourcing equipment. The method comprises the steps of: (a) receiving, atEthernet ports in the multichannel streaming audio amplifier, powertransmitted over each of the plurality of Ethernet cables and audio datatransmitted over one of the plurality of Ethernet cables; (b) combiningthe power received from the plurality of Ethernet cables to power amicroprocessor subsystem and a digital audio amplifier in themultichannel streaming audio amplifier; (c) processing the audio data bythe microprocessor subsystem to generate output audio signals; (d)amplifying the output audio signals by the digital audio amplifier; and(e) outputting the audio output signals amplified by the digital audioamplifier to a plurality of speaker devices for rendering by theplurality of speaker devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an exemplary audio networkincluding a PoE powered multichannel streaming audio amplifier inaccordance with one or more embodiments.

FIG. 2 is a block diagram illustrating an exemplary system architectureof the PoE powered multichannel streaming audio amplifier in accordancewith one or more embodiments.

Like or identical reference numbers are used to identify common orsimilar elements.

DETAILED DESCRIPTION

Various embodiments disclosed herein relate to a PoE poweredmultichannel streaming audio amplifier.

Standardized low-voltage computer Ethernet cables can carry up to 90Watts of power under current IEEE 802.3bt PoE standards. Althoughattractive for its 90 Watt capacity, this standard still does notprovide sufficient power for single-unit commercial audio amplifiers,which can have as many as eight output channels. Various embodimentsdisclosed herein relate to a PoE powered multichannel streaming audioamplifier having dual PoE network connectors. By doubling the networkcables to a single-unit audio amplifier, the amount of power availablecan be doubled utilizing special power electronics circuitry developedto combine the power from each PoE connector input. This increased powersatisfies the first criterion for overcoming the drawbacks of theprevious alternatives discussed above to power commercial audioamplifiers with high-voltage mains circuitry. The second criterion issatisfied by 802.3bt becoming a widely implemented IEEE standard. Sincethe standard's introduction, multiple well-known network switchingequipment vendors have offered switches, routers, and PoE injectors with802.3bt power capacity. The third criterion is satisfied as 802.3btcables are inherently capable of carrying high-speed music service dataallowing the design of devices powered by low-voltage standardizednetwork technology having the ability to access popular music servicessuch as Spotify and Apple Music.

FIG. 1 is a block diagram illustrating an audio network including anexemplary PoE powered multichannel streaming audio amplifier 100 inaccordance with one or more embodiments. The audio amplifier 100includes two Ethernet ports each coupled by an Ethernet cable to an802.3bt standard Power Source Equipment (PSE) device 102. Examples ofPSE devices include PoE enabled network switches and routers. Each PSEdevice 102 supplies power to the audio amplifier 100, and one of the PSEdevices 102 additionally provides streaming audio data to the audioamplifier 100. The audio amplifier 100 processes and amplifies the audiodata for rendering by a plurality of speaker devices 104 connected tothe audio amplifier 100.

FIG. 2 is a block diagram illustrating an exemplary system architectureof the PoE powered multichannel streaming audio amplifier 100 inaccordance with one or more embodiments.

In one or more embodiments, the audio amplifier 100 comprises a singleelectric circuit board assembly 106 containing various components forreceiving and processing power and audio data from connectedstandardized Ethernet cables.

The audio amplifier 100 includes two independent PoE 802.3bt inputcircuits (Powered Device or PD controller circuits) each associated withone of the Ethernet ports. The PD controller circuits can draw powerfrom Ethernet cables also connected to any 802.3bt standard PSE device102. A unique, low-cost electrical subsystem using a single Field-EffectRectifier Diode is used to combine the outputs of the PD controllercircuits without adverse impacts on safety or reliability. This type ofrectifier device features reduced current leakage, which minimizes itsimpact on the operating efficiency of the combined PD controllercircuits.

The Ethernet cables can be connected to two Ethernet sockets 108 a, 108b in the circuit board assembly 106.

Two isolation transformers 110 a, 110 b magnetically couple eachEthernet cable at the sockets 108 a, 108 b to the PD controllercircuits. The isolation transformers 110 a, 110 b act as the ‘frontdoor’, blocking direct current (DC) while allowing alternating currents(AC) to pass. Digital audio data signals exchanged between the device100 and the audio network are passed from the secondary coil of theisolation transformer 110 b to the Ethernet PHY 111 of a microprocessormodule 114.

A special ‘Center Tap’ terminal of the secondary coil of each isolationtransformer 110 a, 110 b is passed to rectifier bridges 116 a, 116 b,which convert the PoE AC signal to a DC form. This is then processed bythe PoE controllers 118 a, 118 b. The PoE controllers 118 a, 118 bestablish power recovery from the network cable after automaticallyidentifying the ‘PoE Class’ or power level that is available from theparticular network the device's Ethernet sockets 108 a, 108 b areconnected to.

A Field-Effect Rectifier Diode (FERD) 120 combines the current recoveredfrom each of the PoE Controllers 118 a, 118 b. This effectively doublesthe current available to the two loads (the microprocessor subsystem 114and the multichannel power amplifier 122). In one or more exemplaryembodiments, the FERD 120 comprises a Schottky diode, which provideshigh speed switching and has a low forward voltage drop and a suitablecurrent rating.

Two DC-DC converters 124 a, 124 b convert the high DC voltage recoveredfrom the previous PoE Controller stage 118 a, 118 b to two lowervoltages required by the digital audio amplifier 122 (24 VDC) and themicroprocessor subsystem 114 (5 VDC)).

The digital audio amplifier 122 amplifies audio signals received fromand processed by the microprocessor subsystem 114.

Audio output signals amplified by the digital audio amplifier 122 aretransmitted the speaker devices 104 via audio outputs 132.

In one exemplary embodiment, the microprocessor subsystem 114 includes a1 GHz ARM A53 processing core 126 and supports a minimum of 256Megabytes of high-speed random-access memory (RAM) 128. The processingcapacity of the microprocessor 126 facilitates processing ofhigh-resolution audio data streams pulled from music services through aconnected PoE enabled networking router and its Internet connection.

The microprocessor subsystem's operating power budget allows executionof an advanced operating system such as, e.g., the full BluOS™ networkedoperating system available from Lenbrook. BluOS™ facilitates connectionto iOS™ and Android™ devices running a BluOS™ software app. This appfunctions as a user control device for the audio amplifier.

Power supplied to the microprocessor subsystem 114 enables effective useof flash memory 130, e.g., up to 64 Gigabytes of flash memory. The flashmemory 130 allows for storage or ‘caching’ of the most popular music andcan be particularly useful in commercial audio installations (e.g.,restaurants and hotels) that must maintain continuous music playback inthe event of Internet or music service outages.

In the exemplary embodiment shown in the drawings, the audio amplifier100 includes two Ethernet ports. In alternative embodiments, the audioamplifier 100 can include more than two Ethernet ports such that powerfrom additional Ethernet cables can be combined to further increase theavailable power.

Having thus described several illustrative embodiments, it is to beappreciated that various alterations, modifications, and improvementswill readily occur to those skilled in the art. Such alterations,modifications, and improvements are intended to form a part of thisdisclosure, and are intended to be within the spirit and scope of thisdisclosure. While some examples presented herein involve specificcombinations of functions or structural elements, it should beunderstood that those functions and elements may be combined in otherways according to the present disclosure to accomplish the same ordifferent objectives. In particular, acts, elements, and featuresdiscussed in connection with one embodiment are not intended to beexcluded from similar or other roles in other embodiments. Additionally,elements and components described herein may be further divided intoadditional components or joined together to form fewer components forperforming the same functions.

Accordingly, the foregoing description and attached drawings are by wayof example only, and are not intended to be limiting.

1. A power-over-Ethernet (PoE) powered multichannel streaming audioamplifier, comprising: a plurality of Ethernet ports, within the PoEpowered multichannel streaming audio amplifier, each configured to becoupled to an Ethernet cable and capable of receiving power and audiodata transmitted over the Ethernet cables; power supply circuitry,within the PoE powered multichannel streaming audio amplifier, connectedto the Ethernet ports and configured to combine and manage the powerreceived at the Ethernet ports; a microprocessor subsystem, within thePoE powered multichannel streaming audio amplifier, powered by the powersupply circuitry and configured to receive and process the audio data togenerate output audio signals; a digital audio amplifier, within the PoEpowered multichannel streaming audio amplifier, powered by the powersupply circuitry, said digital audio amplifier amplifying the outputaudio signals received from the microprocessor system; and a pluralityof audio outputs connected to the digital audio amplifier, each of saidaudio outputs configured to be connected to a different one of aplurality of speaker devices to transmit the audio output signalsamplified by the digital audio amplifier to the plurality of speakerdevices.
 2. The PoE powered multichannel streaming audio amplifier ofclaim 1, wherein the power supply circuitry includes a Field-EffectRectifier Diode for combining the power received at each of theplurality of Ethernet ports.
 3. The PoE powered multichannel streamingaudio amplifier of claim 1, wherein the power supply circuitry includesa plurality of isolation transformers, each magnetically coupled to adifferent one of the plurality of Ethernet ports for blocking directcurrent while allowing alternating current to pass through the isolationtransformer.
 4. The PoE powered multichannel streaming audio amplifierof claim 3, wherein the audio data received at one of the plurality ofEthernet ports is passed from a transformer coil of the isolationtransformer coupled to the Ethernet port to the microprocessorsubsystem.
 5. The PoE powered multichannel streaming audio amplifier ofclaim 3, wherein the power supply circuitry further comprises aplurality of rectifier bridges, each connected to a different one of theplurality of isolation transformers for converting the alternatingcurrent passed through each isolation transformer to direct current. 6.The PoE powered multichannel streaming audio amplifier of claim 5,wherein the power supply circuitry further comprises a plurality of PoEcontrollers, each connected to a different one of the plurality ofrectifier bridges for processing the direct current from each rectifierbridge.
 7. The PoE powered multichannel streaming audio amplifier ofclaim 6, wherein each PoE controller is configured to establish powerrecovery from a connected Ethernet cable after automatically identifyingan available power level from power sourcing equipment to which theEthernet cable is connected.
 8. The PoE powered multichannel streamingaudio amplifier of claim 6, wherein the power supply circuitry furthercomprises a Field-Effect Rectifier Diode connected to the outputs of theplurality of PoE controllers for combining the direct current processedby the plurality of PoE controllers.
 9. The PoE powered multichannelstreaming audio amplifier of claim 8, wherein the Field-Effect RectifierDiode comprises a Schottky diode.
 10. The PoE powered multichannelstreaming audio amplifier of claim 8, wherein the power supply circuitryfurther comprises a DC-DC converter connected to the Field-EffectRectifier Diode and to the microprocessor subsystem for converting thedirect current voltage at the Field-Effect Rectifier Diode to a lowervoltage for the microprocessor subsystem.
 11. The PoE poweredmultichannel streaming audio amplifier of claim 10, wherein the lowervoltage for the microprocessor subsystem is 5 VDC.
 12. The PoE poweredmultichannel streaming audio amplifier of claim 8, wherein the powersupply circuitry further comprises a DC-DC converter connected to theField-Effect Rectifier Diode and to the digital audio amplifier forconverting the direct current voltage at the Field-Effect RectifierDiode to a lower voltage for the digital audio amplifier.
 13. The PoEpowered multichannel streaming audio amplifier of claim 12, wherein thelower voltage for the digital audio amplifier is 24 VDC.
 14. The PoEpowered multichannel streaming audio amplifier of claim 1, wherein thepower and audio data are received over the Ethernet cables from powersourcing equipment.
 15. The PoE powered multichannel streaming audioamplifier of claim 14, wherein the power sourcing equipment comprises apower over Ethernet enabled network router.
 16. The PoE poweredmultichannel streaming audio amplifier of claim 1, wherein the audiodata comprises a high-resolution digital audio stream from an onlinemusic service.
 17. The PoE powered multichannel streaming audioamplifier of claim 1, wherein the plurality of Ethernet ports are eachconfigured to receive power according to the IEEE 802.3bt standard. 18.The PoE powered multichannel streaming audio amplifier of claim 1,wherein the plurality of Ethernet ports are each configured to receive90 Watts of power.
 19. The PoE powered multichannel streaming audioamplifier of claim 1, wherein the plurality of Ethernet ports comprisesexactly two Ethernet ports.
 20. The PoE powered multichannel streamingaudio amplifier of claim 1, wherein the plurality of audio outputscomprises 4 to 8 audio outputs.
 21. The PoE powered multichannelstreaming audio amplifier of claim 1, wherein the power supplycircuitry, the microprocessor subsystem, and the digital audio amplifierare integrated in one or more circuit boards in a housing of the audioamplifier.
 22. The PoE powered multichannel streaming audio amplifier ofclaim 1, wherein the power supply circuitry provides an output of about24 Volts DC to the digital audio amplifier and an output of about 5Volts DC to the microprocessor subsystem.
 23. The PoE poweredmultichannel streaming audio amplifier of claim 22, wherein the powersupply circuitry includes a step-down switch-mode power supply circuitthat converts 24 Volt DC to 5 Volts DC.
 24. A method of operating amultichannel streaming audio amplifier connected by a plurality ofEthernet cables to power-over-Ethernet (PoE) enabled power sourcingequipment, the method comprising the steps of: (a) receiving, atEthernet ports in the multichannel streaming audio amplifier, powertransmitted over each of the plurality of Ethernet cables and audio datatransmitted over one of the plurality of Ethernet cables; (b) combiningthe power received from the plurality of Ethernet cables to power amicroprocessor subsystem and a digital audio amplifier in themultichannel streaming audio amplifier; (c) processing the audio data bythe microprocessor subsystem to generate output audio signals; (d)amplifying the output audio signals by the digital audio amplifier; and(e) outputting the audio output signals amplified by the digital audioamplifier to a plurality of speaker devices for rendering by theplurality of speaker devices.
 25. The method of claim 24, wherein step(b) is performed using a Field-Effect Rectifier Diode in themultichannel streaming audio amplifier.
 26. The method of claim 24,wherein step (b) further comprises using isolation transformersconnected to the Ethernet ports to block direct current from theEthernet cables while allowing alternating current to pass through theisolation transformers.
 27. The method of claim 26, wherein step (b)further comprises using a plurality of rectifier bridges, each connectedto a different one of the plurality of isolation transformers forconverting the alternating current passed through each isolationtransformer to direct current.
 28. The method of claim 27, wherein step(b) further comprises using a plurality of PoE controllers, eachconnected to a different one of the plurality of rectifier bridges forprocessing the direct current from each rectifier bridge.
 29. The methodof claim 28, wherein step (b) comprises using a Field-Effect RectifierDiode connected to the outputs of the plurality of PoE controllers forcombining the direct current processed by the plurality of PoEcontrollers.
 30. The method of claim 28, wherein step (b) furthercomprises using a DC-DC converter connected to the Field-EffectRectifier Diode and to the microprocessor subsystem for converting thedirect current voltage at the Field-Effect Rectifier Diode to a lowervoltage for the microprocessor subsystem.
 31. The method of claim 30,wherein the lower voltage for the microprocessor subsystem is 5 VDC. 32.The method of claim 28, wherein step (b) further comprises using a DC-DCconverter connected to the Field-Effect Rectifier Diode and to thedigital audio amplifier for converting the direct current voltage at theField-Effect Rectifier Diode to a lower voltage for the digital audioamplifier.
 33. The method of claim 32, wherein the lower voltage for thedigital audio amplifier is 24 VDC.
 34. The method of claim 24, whereinthe audio data comprises a high-resolution digital audio stream from anonline music service.
 35. The method of claim 24, wherein the pluralityof Ethernet ports are each configured to receive power according to theIEEE 802.3bt standard.
 36. The method of claim 24, wherein the pluralityof Ethernet ports are each configured to receive 90 Watts of power.